20190513 14:55 
[PUBDB201902239]
Report/Journal Article
Braun, V. M. ; Manashov, A. N. ; Moch, S.O. ; et al
Conformal symmetry of QCD in ddimensions
[DESY18175; arXiv:1810.04993]
QCD in $d=42\epsilon$ spacetime dimensions possesses a nontrivial critical point. Scale invariance usually implies conformal symmetry so that there are good reasons to expect that QCD at the critical point restricted to the gauge invariant subsector provides one with an example of a conformal field theory. [...]
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20190415 11:51 
[PUBDB201901952]
Report/Journal Article
Braun, V. M. ; Manashov, A. ; Moch, S.O. ; et al
Twoloop evolution equations for flavorsinglet lightray operators
[arXiv:1901.06172; DESY18202]
QCD in noninteger $d=42\epsilon$ spacetime dimensions enjoys conformal invariance at the special finetuned value of the coupling. Counterterms for composite operators in minimal subtraction schemes do not depend on $\epsilon$ by construction, and therefore the renormalization group equations for composite operators in physical (integer) dimensions inherit conformal symmetry. [...]
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20190322 09:15 
[PUBDB201901665]
Report/Journal Article
Kramer, G. ; Spiesberger, H.
$b$hadron production in the generalmass variableflavornumber scheme and the LHC data
[arXiv:1809.04297; DESY18154; MITP18085]
We study inclusive $b$hadron production in $pp$ collisions at the LHC at different centerofmass energies and compare with experimental data from the LHCb and CMS collaborations. Our predictions for cross sections differential in the transverse momentum and (pseudo)rapidity agree with data within uncertainties due to renormalization scale variations [...]
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20190314 13:47 
[PUBDB201901539]
Report/Journal Article
Kramer, G. ; Spiesberger, H.
$\Lambda_b^0$baryon production in pp collisions in the generalmass variableflavournumber scheme and comparison with CMS and LHCb data
[DESY18036; arXiv:1803.11103; MITP18020]
We calculate the nexttoleadingorder cross section for the inclusive production of $\Lambda_b$ baryons in pp collisions in the generalmass variableflavornumber scheme. We use realistic evolved nonperturbative fragmentation functions obtained from fits to Bmeson production in $e^+ e^$ annihilation and compare our results for transversemomentum and rapidity distributions with recent experimental data from the CMS and the LHCb collaborations at the CERN LHC. [...]
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20190218 15:45 
[PUBDB201901145]
Report/Journal Article
Braun, V. M. ; Ji, Y. ; Manashov, A. N.
Integrability in heavy quark effective theory
[arXiv:1804.06289; DESY18056]
It was found that renormalization group equations in the heavyquark e ectivetheory (HQET) for the operators involving one e ective heavy quark and light degrees offreedom are completely integrable in some cases and are related to spin chain models withthe Hamiltonian commuting with the nondiagonal entry C(u) of the monodromy matrix.In this work we provide a more complete mathematical treatment of such spin chains inthe QISM framework. We also discuss the relation of integrable models that appear in the HQET context with the largespin limit of integrable models in QCD with light quarks. [...]
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20190218 12:04 
[PUBDB201901141]
Preprint/Report
Herzog, F. ; Moch, S. ; Ruijl, B. ; et al
Fiveloop contributions to lowN nonsinglet anomalous dimensions in QCD
[arXiv:1812.11818; Nikhef2018066; DESY18227; LTH1191]
We present the first calculations of nexttonexttonexttonexttoleading order (N 4 LO) contributions to anomalous dimensions of spin N twist2 operators in perturbative QCD. Specifically, we have obtained the respective nonsinglet quark–quark anomalous dimensions at N=2 and N=3 to the fifth order in the strong coupling αs . [...]
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20190128 13:28 
[PUBDB201900784]
Preprint/Report
Braun, V. M. ; Manashov, A. ; Moch, S. ; et al
Twoloop evolution equations for flavorsinglet lightray operators
[arXiv:1901.06172; DESY18202]
QCD in noninteger $d=42\epsilon$ spacetime dimensions enjoys conformal invariance at the special finetuned value of the coupling. Counterterms for composite operators in minimal subtraction schemes do not depend on $\epsilon$ by construction, and therefore the renormalization group equations for composite operators in physical (integer) dimensions inherit conformal symmetry. [...]
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20181213 15:06 
[PUBDB201805453]
Report/Journal Article
Kniehl, B. A. ; Pikelner, A. ; Veretin, O.
Threeloop effective potential of general scalar theory via differential equations
[arXiv:1810.07476; DESY 18173; DESY18173]
We consider the scalar sector of a general renormalizable theory and evaluate the effective potential through three loops analytically. We encounter threeloop vacuum bubble diagrams with up to two masses and six lines, which we solve using differential equations transformed into the favorable ϵ form of dimensional regularization. [...]
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20181119 13:52 
[PUBDB201804610]
Report/Journal Article
Ji, Y. ; Manashov, A.
Operator mixing in fermionic CFTs in noninteger dimensions
[arXiv:1809.00021; DESY18149]
We consider the renormalization of fourfermion operators in the critical QED and SU(Nc) version of the GrossNeveuYukawa model in noninteger dimensions. Since the number of mixing operators is infinite, the diagonalization of an anomalous dimension matrix becomes a nontrivial problem. [...]
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20181105 13:50 
[PUBDB201804145]
Report/Journal Article
He, Z. ; Kniehl, B. A. ; Wang, X. P.
Breakdown of Nonrelativistic QCD Factorization in Processes Involving Two Quarkonia and its Cure
[arXiv:1809.07993; DESY18168]
We study inclusive processes involving two heavy quarkonia in nonrelativisitic QCD (NRQCD) and demonstrate that, in the presence of two Pwave Fock states, NRQCD factorization breaks down, leaving uncanceled infrared singularities. As phenomenologically important examples, we consider the decay $\Upsilon \to \chi_{cJ}+X$ via $b\bar{b}({}^3P_{J_b}^{[8]})\to c\bar{c}({}^3P_J^{[1]})+gg$ and the production process $e^+e^\to J/\psi+\chi_{cJ}+X$ via $e^{+}e^{}\to c\bar{c}({}^3P_{J_1}^{[8]})+c\bar{c}({}^3P_J^{[1]})+g$. [...]
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